Soil treating process



Feb. 4, 1947. F. H. LEAVITT SOI L TREATING PROCESS Filed Feb. 11, 1944 2 Sheets-Sheet l u 2 n r m .T A .m h H B Feb, 4, 1947. F. H. LEAVITT SOIL TREATING PROCESS Filed Feb. 11, 1944 2 Sheets-Sheet 2 Fig. 2

lnvenrori Flogd H. Lem/HT.

Patented Feb. 4, 1947 SOIL TREATING PROCESS Floyd H. Leavitt, Burlingame, Calif., assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application February 11, 1944, Serial No. 522,202

Claims.

The present invention relates to soil treating methods and pertains more particularly to an improved method of distributing fumigants, disinfectants and fertilizers throughout soils.

Heretofore, fumigants for controlling harmful soil organisms have been introduced into the soil in various Ways, such as by pouring a measured amount of the treating agents into spaced holes, flowing the agents out of pipes attached behind cultivator shoes, spraying thesoil surface in combination with subsequent disking or harrowing, etc. All of these prior methods are unsatisfactory for one or more of the following reasons: insufficient distribution and penetration throughout the soil, high evaporation losses which increase the amount of agent necessarily used and thereby the expense of treating, high cost of treating due to the many manipulative and laborious stepsinvolved in applying the agents, long periods necessary for efficiently treating, etc.

Itisespecially important in the .case of soil fumigants that a wide distribution and deep penetration throughout the soil be obtained in order to control harmful soil organisms, such as nematodes, root-rotting fungi, Sclerotium roljsii, southern root rot, oak root fungus in peach and citrus trees, wire worms, etc. The nematode or eelworm is a. particularly troublesome soil pest and is Wldelydistributed in soils throughout the world. Its: many species attack almost all. plants and trees including most food crops. For example, one species, Heterodera mariom', which is distributed throughout the temperate, subtropical and tropical regions of the world, attacks more than 800 plants. The attacks by nematodes weaken plants and cause them to become diseased. However, in spite of considerable effort and research, no satisfactory control of nematodes has heretofore been widely used. Although highly toxic soil fumigants may have been developed, the lack of success in controlling nematodes and the like is due at least in part to'the poor distribution and penetration of the agents through the soil. r

It is therefore an object of 'this inventlon to provide an improved method ofdistributingfumigants, distinfectants, fertilizers and the like throughout soil's.

It is another object of this invention to provide an apparatus for carrying outthe present method.

The accompanying drawings illustrate a preferredembodiment of an apparatusfor carrying out the present invention.

Figure 1 illustrates.- in. perspective. View a. sub:- surface-1 liquid: atomizing machine:

Figure Zillustrates in vertical cross-section a preferred embodiment of the atomizing nozzle of said atomizing machine.

Figure 3 illustrates in vertical cross-section another embodiment of an atomizing nozzle.

The method of the present invention briefly comprises atomizing under the soil surface a liquid soil treating agent with a gas. The method is especially applicable to the distribution of fumigants throughout the soil in order to control harmful soil organisms such as nematodes.

Although many soil fumigating agents may be used to some advantage in the present process, it is preferred to use halogenated, especially polyhalogenated, unsaturated lower hydrocarbons, particularly those of 3 to 6 carbon atoms. A highly effective group of agents are the allylvinyl type polyhalo, preferably dihalo, unsaturated hydrocarbons of 3 to 6 carbon atoms, particularly those of 3 carbon atoms. In this class, it is preferably that one of the halo groups be on a terminal carbon atom. An especially effective compound of this class is 1,3-dichloroprop'ene-1. A highly useful mixture containing 55% to of this compound along with 15% to40%= of 1,2- dichl'oropropane and 0% to 20 of higher boiling materials consisting mainly of trichloroand tetra-chloropropane may be obtained as a byproduct from the high temperature chlorsubstitution of propylene in the manufacture of allyl chloride under certain conditions; Other preferred agents include 1,1-dihalopropene-2 and theZ-alkyt homologues thereof, wherein the alkyl substituent has:1 to 3 Carbon atoms, e. g". 1,1-dichloropropene-Z, l,l-dichl'oro-Z-methylpropene- 2, etc.,. and v diallyl ty-pe polyhalo, preferably dihalo", unsaturated hydrocarbons of 4 carbon atoms which have the halo groups on different carbon: atoms, e. g. lA-dichlorobutene-Z and 1- chloro-2-chloromethylpropene-2. Generally most effective. are the compounds or mixtures thereof which. have a boiling range of 75 C. to C.

Other halogenated organic compounds, preferablyh'avingiless than 20 carbon atoms, are also suitable: Therem'ay' be mentioned, for example, halogenated carboxylic acids, halogenated esters of. carboxylic acids, halogenated ketones', substituted derivatives thereof, and the like. The halogenated compounds of this type having less than 8 carbon atoms are preferred. The halogenated organic compounds described above may,-in some cases, contain other substituents', such as hydroxy, thio'cyan'o, nitro, amino,.imino, carbonyl, ether; thioether, mer'capto, etc.

It isv usually preferableto add small amount of stabilizers" to such halogenated organic. com- .ized with ammonia gas,

pounds. Suitable stabilizers include hydrochloride-acceptors and the like, such as, for example, epichlorhydrin, propylene oxide, ethylene oxide, methyl'vinyl ketone, acrolein, amyl amine, dimethyl amine, ammonia, ethanol amine, dihydroisophoronyl amine, glycerol, lime water, etc.

While the halogenated compounds are preferred soil fumigants, other soil treating agents, such as phosphoric acid, etc., may be used in the general method of the present invention.

Suitable gases or vaporous materials which may be utilized or atomizing the liquid soil treating agents include ammonia, nitrogen, hydrocarbon gases or their halogenated derivatives or mixtures thereof such as methane, ethane, ethylene, propane, propane-propylene and butane-butylene fractions of petroleum, dichlorodifluoromethane, dichlorotetrafiuoroethane, and the like. The term vaporous materials is intended to include .both normally gaseous materials as well as materials having a sufliciently high vapor pressure to be at least partially, vaporized at thetemperature of application. Thus, for example, partially vaporized liquid anhydrous ammonia or the like may be used. However, it is preferable that the atomizing agent is mainly in the vaporized state when it reaches the atomizing nozzle; The atomizing gas need not be completely inert to the liquid soil treating agent but only relatively inert. For example, the above mentioned chlorinated C3 mixture, containing 1,3-dichloropropane, 1,2-dichloropropane and some trichloropropenes and propanes. have been found to be effectively atom- This combination of atomizing halogenated unsaturated lower hydrocarbons with ammoniaisparticularly desirable since the harmful soil organismssuch as nematodes are'eifectively eradicated while at the same time a quicklyeassimilatable nitrogen-containing fertilizer is being introduced into the soil. The injection of anhydrous ammonia alone into soil is disclosed in prior Leavitt U, S. Patents 2,285,932 and 2,306,339.

- .The quantities of the liquid soil treating agents and atomizing gas depend upon the nature of the imaterials used, the general condition of the soil,

the time of application, etc., and, in the case of ammonia, on the nature of the crop. For example, when using the above-mentioned mixture containing 1,3-dichloropropene-1 and 1,2-dichloropropane as the fumigating agent, an application rateof '75 to 400 pounds per acre and preferably from 100 to 250. pounds per acre is used. -When using agents, such as 1,3-dichloropropene-1 in. relatively pure form, lesser amounts, such as 50 to 200 pounds per acre, of the fumigating agent are. preferred. When using ammonia as the atomizing'gas, excellent results are obtained by using to 150 pounds of ammonia per acre, the lesser amounts being used with grain crops and the heavier amounts being used with vegetables. Particularly effective results, including high kill .of nematodes and use of a minimum amount of soil, fumigant, are obtained whenthe atomization is effectedat least 2 inches, and preferably 3 to 8 inches, below the soil surface. Greater depths may beused, if desired, the proper depth depending on the nature of the soil, its physical texture or,looseness, etc. Y

The atomization of the liquid soil treating agentswith gaseous materials is preferably performed by means of an atomizing nozzle carried imderground behind a cultivator shoe or other suitable ground working tool, The. liquid soil treating agent, preferably under a positive pres- 4 sure, and the gaseous atomizing agent are separately conducted to the atomizing nozzle by means of pipes leading from supply sources of the two materials.

Referring to Fig. l of the drawings, a preferred embodiment of an apparatus for carrying out the present method comprises a wheeled farm tractor Ill having a suitable toolbar I I or the like, which preferably may be raised or lowered for manipulation of ground-working tools, such as cultivator blades I2a and I2b, carried by said tool or gang bar I I. The mechanism for raising and lowering the tool bar I I comprises a pair of horizontal bars I3 hung from the chassis of the tractor III by means of pivoted pendants I4. Horizontal bars I3, upon the rear ends of which are attached the tool bar I I, ar swung backwards and downwards or forwards and upwards by means of a piston rod I6 which is actuated by a hydraulic piston adapted to reciprocate by hydraulic pres-- hood of the tractor II]. A conduit 2| leads from the furnigant cylinder 20 through shut-off valve 22 to manifold 23. Outlets 24a and 24b in spaced position on said fumigant manifold 23 are pro vided for each cultivator In and I2b. Connected to outlet 24a is a shut-off valve 25, which is provided withan interchangeable flow-control orifice 26 or other suitable flow-controlling device. (A similar shutofi valve and flow-control orifice is provided for outlet 24b, but is not shown for purposes of clarity in the drawings.) Leading from said orifice 26 is a flexible conduit 21a which passes down the rear of the cultivator blade 12a. A similar flexible conduit 2'") passes down the rear of blade I212. The conduits 21a and 21b lead to atomizing nozzles 28a and 28b, respectively, rigidly mounted behind the cultivator shoes'29a and 2% which form the lower end of the cultivator blades I2a and IZb, respectively. V

In case air is used as the atomizing gas, an air compressor 35 may be mounted on the tractor floor'behind the drivers seat 36. The air compressor 35 may use a power take-off from the tractor drive-shaft by means of a pulley 31 on the compressor Y15 and a belt 38.. ,From the air compressor 35 a conduit 39 leads to a-Y, one branch 400i; which leads through valve M to atomizing gas manifold 42, and the other branch 43, including control. valve 4301,, leads to the positive-pressure system, as described hereinbelow. The atomizing gas manifold 42 isprovided with spaced outlets 44a and 44b. Outlet 44a is provided with valve 45 and flow-controlling means, such as a replaceableorifice 46. Likewise, butinot shown, outlet 44b is provided with a-valve and orifice: Leading from said orifice 46 ,isafiexible conduit 410. which passes down'therear of. the cultivator blade I2a to the atomizing nozzle. -.A similar flexible conduit .41!) passes. downfith'e rear of. cultivator blade, I212. The air-compressor 3.5 may be adjusted to give an air pressure of about 30 pounds per sq. in., although higherlorlower pressures may be used. 1 "p. 3

The conduit branch 43 leads to an air receiver 50 mounted over the tractor enginehood'. Contained in said conduit branch 43 is a safety or relief valve 5|, which may be suitably set at-50 lbs. per sq. in. The relief pressure, may, however, be set lower or higher, such as 110 to .75 lbs.

antes;

treating agent, the diameter of'the conduits, etc. Leading from conduit branch 43 is a conduit 52, which is provided with a pressure regulating valve 53 and opens into the top of the supply cylinder 20for the liquid soil treating agent. When using the halogenated unsaturated lower hydrocarbons,

the pressure regulating valve may be set at about 20 pounds per sq. in., although higher or lower pressures may be used, depending on conditions, as, desired.

' In case a compressed atomizing agent, such as ammonia, is used as the atomizing gas, another cylinder 60 is suitably mounted over the tractor engine hood. From the ammonia cylinder '60 a conduit SI leads through valve 62 to'the atomizing'gas manifold 42. Naturally when usingammonia, valve 62 is open and the air control valve 4| "is closed. f Likewise, when ,using air, said valves 62 and 4| are in the opposite position.

Referring to Figure 2, showing a preferred nozzle in detail, the nozzle 28a (and similarly nozzle 287:) comprises a nozzle body which is fastened, such as by welding as indicated at 11, to the rear of the cultivator shoe 29a. Into the rear of the nozzle body 10 is a large, horizontal, and at least partially threaded bore 12. Extending from said lfil'ge'bore 12 into the nozzle body 10 is a smaller bur-e13; Extending from the upper face of the nozzle body 10 through to -the large bore 12 is a threaded bore 14, into which is screwed the end of the conduit 21a for the liquid soil treating agent, Another threaded bore 15 extends from the upper face of the nozzle body 10 to the inner end of the narrow horizontal bore 13. The upper threaded portion of the bore 15 is adapted to receive the atomizing gas conduit 41a and the lower portion of the bore 15 may be constricted to approximately the size of the narrow horizontal bore 13.

Threaded into the large horizontal bore 12 is an outer nozzle sleeve 16 having perforations 11 in the annulus opposite the vertical bore 14. The

bore through the sleeve 16 is constricted at 18 in the outer end to form a nozzle outlet 19 with outwardly tapered faces 80. A gas conducting sleeve 82 is held within the outer nozzle sleeve 16 by the action of the inher end of the outer sleeve 16 against the flange 83 on the inner end of inner sleeve 82. The outer end of the gas-conducting sleeve 82 is constricted to form a small port 84 spaced from said orifice outlet 19. Gas passing --through the inner sleeve and port 84 and liquid flowing through perforations 11 from conduit 21a 'into the annular space 85 between the two sleeves 16 and 82 causes tween the inner outlet 19.

In one experiment using air, the fiow-controlling orifices (e. g., 26 and 46) were selected to give 2% cubic feet per minute of air at pounds per sq. in. and 55 pounds propene-propane dichlorides mixture. At normal tractor speeds with cultivator blades I2a and I2b spaced 18 inches apart, thi yields about 90 pounds per acre of said propene-propane dichlorides mixture. By using the same air flow rate and blade spacing but with larger orifices, the flow of the chlorinated propene-propane mixture was increased to about 675 cc. per minute to give a treatment of about 2 00 pounds per acre of said mixture at a tractor speed of 260 feet per minute.

In another experiment, ammonia gas was used at the rate of 11 cu. ft. of partially vaporized ammonia per minute. At normal tractor speeds and 18 inch spacing of the cultivator blades I 211 and atomization to take place besleeve port 84 and outer sleeve in the nipple member 95 6 Izb, this rate is equivalent to about. 50 pound per acre of ammonia. This rate of ammonia was also effectively used with flow rates for said propenepropane dichlorides mixture to yield and 300 pounds per acre of the dichloride mixture. It will be readily apparent that various modifications and additions may be made in the above described preferred embodiment of suitable apparatus for carrying out the present method with out departing from the spirit of the present invention. For example, it is obvious that more than two cultivator injection blades I2a and [2b may be used. Thus, while only two are shown for simplicity, usually four and sometimes six of such blades are used. Likewise, instead of mounting the supply cylinders 20 and 60 or other suitable tanks over the engine hood, they may be arranged in other positions, such as, for example, on a. trailer drawn by the tractor. Further, if desired, the whole of the injection apparatus, including the supply cylinders 20 and 6.0, the air compressor35 (when used); and the cultivator blades I2a and I2b, may be suitably mounted on a trailer or other suitable farm equipment.

In some cases, it is desirable to provide a nozzle having a pressure-responsive valve which closes when the supply of fumigant to the nozzle is shut off, whereby liquid fumigant in the conduit leading to the nozzle will not drain outafter the fumigant supply control is closed. Referring to Fl'g. 3, a preferred embodidrical member 90, which is attached, such as by welding as indicated at 9I,to the rear of the cultivator shoe 29a. Within the cylindrical member is a fumigant receiving chamber 92, to which *fumigant is displaced through threaded port-. 93

ber 95 having a threaded port 96in its upper portion, to which port 96 is threadably attached the atomizing gas conduit 21a. Positioned withby means of a forward partition plate 98 and rearward perforatedpartition plate 99 is a fumigant conducting tube I-00 having a. valve seat IOI formed at its rearward end, Extending through the tube I00 is a. valve stem I02 carrying a valve I03 cooperating with the valve jseatl M to controlthe flow through "the tube I00. Under no-pressure conditions the valve is, held closed by means of a coil spring I05 surrounding the forward end of the tubefI00 and acting against the partition plate 98 anda spring retaining spider I 06 fastened to a. threaded nut I01 carried on the forward threaded end I08 of the valve stem I02. I01 carrying the spider I06 is adapted to be held at the desired position on the valve stem I02 by means of a lock nut I09. By adjusting the position of the nut I01 the spacing between the ends of the spider I06 and the partition plate 98 is determined, whereby the amount of maximum opening of the valve I03 is regulated.

To the rearward threaded end H5- of the nipple member 95 is threadably attached a clamp member H6, which holds a tubular flanged head member II1 against the gasket H8 or packing means between said head member H1 and the end 5 of the nipple member 95. Threaded into the threaded bore H 9 of the head member H1 is a suitable tubular nozzle tip I20.

In operation, the pressure of the spring I05 is insufiicient to hold the valve I 03 in closed posivalv 22 or the like The improved the soil surfaceand lful. soil organisms ,tions on the valveseat lfll against the pressure of. the liquid fmnigant enteringithe"tube 1110 from" the chamber 92 andsupply'conduit 41a". Atomizing 'gas,. fsuch as. air,.,ent'e1ging through supply conduit 21a, passes" through the perfo rated partition 'plate 98 to the atomizingchamber I25, where atomization of the-liquid iumigant issuing from tube I takes, place. Thereafter the atomized mixture passes" out throughthe tubular nozzle tipl20. T j v i 1 Whenfthe pressure flow of liquidjfumigant to {the nozzle is stopped, such as by'closing valve 22 ,v,(Fig, 1) the, action of the spring I05 against thflretaining Vspiderfcauses the valve ill? to be closed against the valve seat llll andto prevent further fumigant from entering the atomizing :chamber 125. This." avoids dripping of, liquid fumigant whenthe end ofa crop row is reached orfat. any'othertirhe that it maybe desired to temporarily stop the machine or flow oi liquid fumigant, Also, back-flow of atomizing gas into theliquid f umigant conduits or supply tanks is avoided,v since whenthe, liquid fumigant flow is stopped, the pressure of the atomizing gas in the atomizing chamber 125,.acts, in addition to spring l05,to close valve I03.

I .The above described apparatus is vclaimed in eopending 552,525, filed September 2,1944} divisional application, Serial No.

I claim as my invention:

1. The improved method oi controlling harmful soilorganisms comprising atomizing' below the soil surface and in the vicinity of said organ isms a liquid soil funngantby means of a vaporous ammonia-containing 1 plant servingas the atomizing agent. 7

v method of controlling harm- Iful soil organisms-comprising atomizing below the soil surface and in the vicinity 'of said organismsfaliquid soil fumigantwith a gaseous ammonia-said gaseous ammonia serving as the food, said latter .atomizing agent.

' ,3. The improved methodof controlling harmful soil organisms comprising atomizin'g below in thevicinity of said organisms a. liquid soil fumigant by means of anhydrous ammonia, said atomizing agent. I V t 14., The impIOVed method of controlling harmcomprising introducing below the. soil surface and in the vicinity of said organisms a halogenated organic compound select.- edflfro'rn the group consisting of halogenated unsaturated lower hydrocarbons, halogenated carboxylic acids,' halogenated esters of carboxylic acids halogenated k 'etones andth'e substituted latter serving as the V a liquid, soil fumigating agent atomizing agent.

derivatives thereof, by means of a vaporous plant stimulant, said latter serving as an atomizing 'agent.f.

,s' r'rne improvedmethodof controll ng harmful soil organisms comprising atomizing a liquid soil fumigant by means of a vaporous' ammoniacontaining plant food, said latter serving as the 'atomizing agent at a depth of atleast 2 inches below the soil surface. 7 v

"6. The method of claim 4 wherein the vaporous plant stimulant comprises a vaporous ammoniacontaining plant food. r .1

7, 'The method of claim 4 wherein the vaporous plant stimulant comprises gaseous ammonia.

-8. A method of treating soilsto stimulate plant growth therein, which comprises introducing a halogenated organic" soil. fumigant containing reactive halogen atoms by means ofa vaporous plant stimulant, the izingagnt. f 9, A method of treating soils containing harmiful soil organisms, which'comprises introducing into andbelow thesurface of'the soil by means of a vaporous plant stimulant, the latter serving as an atomizing agent.

10. A method of treating soils containing harmful soil organisms, which comprises introducing a soil treating agent into i I surface of the soil by means of a vaporous'dissimilar plant stimulant, the latter serving as an latterserving as an atom- 'rLoYn H.- LEAVITI;

REFERENCES orrEn The following references-are of record-in 1; e :file of thispatent: g V;-

UNITED STATES PATENTS r Date Number Name 1,814,446. Irish July-l4, v1931 7 2,285,932 Leavitt' June 9; 1942 1,038,084 Carroll -Sept.10, 1912 1,667,923, Bishop -May 1,1928 317,802 Laborde 'May' 12-, 1885 FOREIGN PATENTS Number. Country Date 843,895 7 French 1 V- Apr. 3, 1939 OTHER. RE ERENCES] I Lehmanflhaboratory Tests of Organic Fu m iga'nts for Wireworms published 1942 in Journal of Economic Entomology, vol.

, 35, pages 659 through661,copy inDiv.,63. L

and below the V 

